Downlink-only fifth generation new radio

ABSTRACT

In aspects of downlink-only fifth generation new radio, a mobile communication device includes a radio frequency transceiver, a radio frequency receiver, and a processor and memory system to implement a radio control manager application that establishes an LTE anchor link with a base station using the LTE transceiver, establishes a 5G NR downlink from the base station to the mobile communication device using the radio frequency receiver, and manages the 5G NR downlink via an uplink of the LTE anchor link. In another aspect, a mobile communication device estimates channel conditions for a 5G NR downlink, selects a precoding matrix to beamform the 5G NR downlink, and provides an indication of the selected precoding matrix via the LTE anchor link.

BACKGROUND

The evolution of wireless communication to fifth generation (5G)standards and technologies provides higher data rates and greatercapacity, with improved reliability and lower latency, which enhancesmobile broadband services. 5G technologies also provide new classes ofservices for vehicular, fixed wireless broadband, and the Internet ofThings (IoT).

A unified air interface, which utilizes licensed, unlicensed, and sharedlicense radio spectrum, in multiple frequency bands, is one aspect ofenabling the capabilities of 5G systems. The 5G air interface utilizesradio spectrum in bands below 1 GHz (sub-gigahertz), below 6 GHz (sub-6GHz), and above 6 GHz. Radio spectrum above 6 GHz includes millimeterwave (mmWave) frequency bands that provide wide channel bandwidths tosupport higher data rates for wireless broadband.

To increase the capacity of 5G radio networks, Multiple Input MultipleOutput (MIMO) antenna systems are used to beamform signals transmittedbetween base stations and user terminals. In 5G networks, a large numberof MIMO antennas (e.g., hundreds of antennas) are employed forbeamforming signals, which is often referred to as Massive MIMO, toprovide beamformed transmission and reception that is focused on smallareas of space around individual user terminals. Massive MIMObeamforming improves network throughput, energy efficiency, andinterference rejection. Massive MIMO systems use a channel estimate ofthe radio frequency (RF) channel characteristics between the basestation and the user terminal to determine beamforming coefficients fortransmission and reception.

The specification of the features in the 5G air interface for userequipment (UE) is defined as 5G New Radio (5G NR). The combination ofsupporting multiple frequency bands, wider channel bandwidths, higherdata rates, and Massive MIMO increases the number of uplink and downlinkprocessing chains, power amplifiers, and RF front end componentsrequired in the UE. For user equipment such as a smartphone, the supportof 5G NR features for both uplink and downlink communication increasespower consumption that reduces the battery life of the smartphone,increases the complexity of managing in-device coexistence problemsrelated to interference during simultaneous operation of Long TermEvolution (LTE) and 5G transmitters, and requires additional componentsthat occupy more space in the constrained mechanical package of thesmartphone, as well as increasing the cost of the smartphone.

SUMMARY

This summary is provided to introduce simplified concepts ofdownlink-only fifth generation new radio. The simplified concepts arefurther described below in the Detailed Description. This summary is notintended to identify essential features of the claimed subject matter,nor is it intended for use in determining the scope of the claimedsubject matter.

In some aspects, a mobile communication device includes a radiofrequency transceiver, a radio frequency receiver, and a processor andmemory system to implement a radio control manager application thatestablishes an LTE anchor link with a base station using the LTEtransceiver, establishes a 5G NR downlink from the base station to themobile communication device using the radio frequency receiver, andmanages the 5G NR downlink via an uplink of the LTE anchor link.

In another aspect, a method of managing a fifth generation new radio (5GNR) downlink from a base station is described, in which a user equipment(UE) establishes a Long Term Evolution (LTE) anchor link with the basestation, establishes the fifth generation new radio (5G NR) downlinkfrom the base station to the UE, and manages the 5G NR downlink via anuplink of the LTE anchor link.

In a further aspect, a system includes an Evolved Universal TerrestrialRadio Access Network Node B (E-UTRAN Node B) and a user equipment (UE)that is configured to establish a Long Term Evolution (LTE) anchor linkwith the E-UTRAN Node B, establish a fifth generation new radio (5G NR)downlink from the E-UTRAN Node B to the user equipment, and manage the5G NR downlink via an uplink of the LTE anchor link.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of downlink-only fifth generation new radio are described withreference to the following drawings. The same numbers are usedthroughout the drawings to reference like features and components:

FIG. 1 illustrates an example wireless network system in which variousaspects of downlink-only fifth generation new radio can be implemented.

FIG. 2 illustrates an example device diagram that can implement variousaspects of downlink-only fifth generation new radio.

FIG. 3 illustrates an example environment in which various aspects ofdownlink-only fifth generation new radio techniques can be implemented.

FIG. 4 further illustrates an example network stack model with whichvarious aspects of downlink-only fifth generation new radio techniquescan be implemented.

FIG. 5 illustrates an example method of downlink-only fifth generationnew radio as generally related to activation of, and data transferusing, an LTE anchor link and a 5G NR downlink in accordance withaspects of the techniques described herein.

FIG. 6 illustrates an example method of downlink-only fifth generationnew radio as generally related to closed-loop beamforming of the 5G NRdownlink in accordance with aspects of the techniques described herein.

FIG. 7 illustrates an example method of downlink-only fifth generationnew radio as generally related to control-plane measurements formobility management and/or channel quality of the 5G NR downlink inaccordance with aspects of the techniques described herein.

FIG. 8 illustrates an example method of downlink-only fifth generationnew radio as generally related to acknowledgements of network layeroperations of the 5G NR downlink in accordance with aspects of thetechniques described herein.

FIG. 9 illustrates an example communication device that can beimplemented in a wireless network environment in accordance with one ormore aspects of the techniques described herein.

DETAILED DESCRIPTION

As wireless communication systems evolve to 5G NR technologies, 5Gnetworks will be deployed in parallel with existing Long Term Evolution(LTE) networks. Both operator networks and user devices willsimultaneously support the use and interoperation of LTE and 5G NRtechnologies. Initial deployments of 5G NR will be focused on dataapplications, such as video streaming to user equipment, with otherservices, such as voice calling, coming later. In these initialdeployments, LTE will provide the other services and provide coverage inareas without 5G NR coverage. An anchor link is established using LTEbetween a base station and a user terminal. A 5G NR link can beestablished between the base station, or another base station in thenetwork, and the user terminal using signaling over the LTE anchor link.

Many data applications that can take advantage of higher 5G NR datarates, especially data rates in the mmWave bands, are asymmetric in theamount of data transferred over the uplink as compared to the downlink.For example, video streaming or web downloads transfer a large amount ofdata over the downlink, but a relatively small amount of data (e.g.,acknowledgements, flow control, Uniform Resource Locators, and the like)over the uplink. In another example, wider 5G NR bandwidths enable fastdownloads of video content that are cached on a user device for laterconsumption by the user. The combination of supporting multiplefrequency bands, wider channel bandwidths, higher data rates, andMassive MIMO increases the number of uplink and downlink processingchains, power amplifiers, and RF front end components required in userequipment. Yet for these applications, the resources that provide 5G NRuplink capacity in the user equipment are underutilized as the uplinkdata throughput for these applications does not require the capacity the5G NR uplink provides.

In aspects, the LTE anchor uplink can be used for uplink communicationassociated with applications using the 5G NR downlink. The data capacityand latency of the LTE anchor uplink is sufficient to support dataapplications using the 5G NR downlink. Using the LTE anchor uplink, forsignaling and uplink communication related to the 5G NR downlink, caneliminate the need to provide support 5G NR uplink in user equipment.This use of downlink-only 5G NR communication eliminates the need forthe user equipment to support a 5G NR uplink with its associatedtransmitter processing chains and transmit power amplifiers.Downlink-only 5G NR reduces components in the user equipment, reducesthe complexity of managing in-device coexistence problems, reduces powerconsumption in the user equipment, and requires less space in the userequipment, while providing the high throughput data downlink experiencea user expects.

In aspects, the user equipment provides feedback to the base station forbeamforming of the 5G NR downlink via the LTE anchor uplink. Forexample, beamforming for Massive MIMO uses closed-loop or beam-indexbeamforming for downlink-only 5G NR. The base station and the userequipment both have a copy of a codebook that includes precodingmatrices for beamforming with an index value (e.g., a precoding matrixindicator or PMI) associated with each precoding matrix in the codebook.The base station transmits cell-specific reference signals (RS)distributed over various resource elements (RE) and/or timeslots of the5G NR downlink. The reference signals are evaluated by the userequipment to estimate channel conditions between the base station andthe user equipment. Based on the channel estimates, the user equipmentselects a precoding matrix to use for beamforming and sends a response,which includes the PMI of the selected precoding matrix, via the LTEanchor uplink, to the base station. The base station uses the selectedprecoding matrix to beamform the 5G NR downlink to the user equipment.Providing beamforming indices for downlink-only 5G NR via the LTE anchorlink reduces components, power consumption, and required space in theuser equipment, while providing beamforming for improving datathroughput and interference rejection to user equipment.

In aspects, the user equipment provides application and network layerfeedback messages over the LTE anchor uplink for data transferred to theUE via the 5G NR downlink. For example, an acknowledgement (ACK) and/ora negative acknowledgement (NACK) is provided by applications and/ornetwork layers in the user equipment to corresponding applicationsand/or network layers at the base station, within the core network, orat a remote service. For data transfers over the 5G NR downlink, the ACKor NACK is transmitted via the LTE anchor uplink. By way of furtherexample, for TCP transfers over the 5G NR downlink, the TCP flow controlpackets are transmitted via the LTE anchor uplink. Providing applicationand network layer feedback for downlink-only 5G NR via the LTE anchorlink reduces components, power consumption, and required space in theuser equipment, while providing application and networking control andresponse messages to support internet-connected communication services.

In aspects, signaling for activation and deactivation, communication ofgrant information, 5G NR downlink measurements, and/or channel qualitymeasurements are communicated between the base station and the userequipment over the LTE anchor link. For example, Radio Resource Control(RRC) messages and/or Media Access Control (MAC) control elements (CE)to activate or deactivate the 5G NR downlink are communicated betweenthe base station and the user equipment over the LTE anchor link. Inaddition to communicating 5G NR activation messages over the LTE anchorlink, the base station can also communicate activation and/ordeactivation messages for the 5G NR downlink over the 5G NR downlink,and/or communicate activation and/or deactivation messages for the LTEanchor link over the 5G NR downlink.

In another example, resource elements (RE) that grant time and frequencyresources to the user equipment for the 5G NR downlink are transmittedfrom the base station to the user equipment over the LTE anchordownlink. The base station can also communicate grant information forthe LTE anchor link via the 5G NR downlink to the user equipment.

In a further example, measurements of the 5G NR link that are used formobility management, such as Received Signal Strength Indicator (RSSI),Reference Signal Received Power (RSRP), and/or Reference Signal ReceivedQuality (RSRQ), or for modulation and coding scheme (MCS) control, suchas the channel quality indicator (CQI), are transmitted to the basestation over the LTE anchor uplink. Providing activation anddeactivation, communication of grant information, 5G NR downlinkmeasurements, and/or channel quality measurements for downlink-only 5GNR reduces components in the user equipment, reduces components, powerconsumption, and required space in the user equipment, while providingapplication and networking control and response messages to supportinternet-connected communication services.

While features and concepts of the described systems and methods fordownlink-only fifth generation new radio can be implemented in anynumber of different environments, systems, devices, and/or variousconfigurations, aspects of downlink-only fifth generation new radio aredescribed in the context of the following example devices, systems, andconfigurations.

FIG. 1 illustrates an example environment 100 which includes a userequipment 102 that communicates with a base station 104 through awireless communication link 106 (wireless link 106). In this example,the user equipment 102 is implemented as a smartphone. Althoughillustrated as a smartphone, the user equipment 102 may be implementedas any suitable computing or electronic device, such as a mobilecommunication device, a modem, cellular phone, gaming device, navigationdevice, media device, laptop computer, desktop computer, tabletcomputer, smart appliance, vehicle-based communication system, and thelike. The base station 104 (e.g., an Evolved Universal Terrestrial RadioAccess Network Node B, E-UTRAN Node B, evolved Node B, eNodeB, eNB, andthe like) may be implemented in a macrocell, microcell, small cell,picocell, and the like, or any combination thereof.

The base station 104 communicates with the user equipment 102 via thewireless link 106, which may be implemented as any suitable type ofwireless link. The wireless link 106 can include a downlink of data andcontrol information communicated from the base station 104 to the userequipment 102 and/or an uplink of other data and control informationcommunicated from the user equipment 102 to the base station 104. Thewireless link 106 may include one or more wireless links or bearersimplemented using any suitable communication protocol or standard, orcombination of communication protocols or standards such as 3rdGeneration Partnership Project Long-Term Evolution (3GPP LTE), 5G NR,and so forth. In aspects, the wireless link 106 includes an LTE anchorlink and a 5G NR downlink.

Alternatively and/or optionally, the wireless link 106 includes an LTEuplink and a 5G NR downlink without an LTE downlink, or the wirelesslink 106 includes an LTE downlink and a 5G NR uplink without an LTEuplink and/or a 5G NR downlink. These configuration are useful toeliminate or repurpose processing chains in the user equipment 102 or toprovide operational flexibility based on variations in wireless networkcoverage. The techniques described herein apply equally to thesealternate and/or optional configurations.

In aspects, the user equipment 102 communicates with an additional basestation 108 via a wireless link 110. The wireless link 110 may beimplemented using the same communication protocol or standard, or adifferent communication protocol or standard, than the wireless link106. For example, the wireless link 106 is an LTE link and the wirelesslink 110 is a 5G NR link. The base station 104, the base station 108,and any additional base stations (not illustrated for clarity) arecollectively a Radio Access Network 112 (RAN 112, Evolved UniversalTerrestrial Radio Access Network 112, E-UTRAN 112), which are connectedvia an Evolved Packet Core 114 (EPC 114) network to form a wirelessoperator network. For example, the base station 104 may be an LTEmacrocell and the base station 108 may be a 5G NR small cell both incommunication with the user equipment 102, the communication beingcoordinated within and/or via the EPC 114. The UE 102 may connect, viathe EPC 114, to public networks, such as the Internet 116 to interactwith a remote service 118.

FIG. 2 illustrates an example device diagram 200 of the user equipment102 and the base station 104. It should be noted that only the essentialfeatures of the user equipment 102 and the base station 104 areillustrated here for the sake of clarity. The user equipment 102includes antennas 202, a radio frequency front end 204 (RF front end204), an LTE transceiver 206, and a 5G NR receiver 208 for communicatingwith base stations 104 in the E-UTRAN 112. The RF front end 204 of theuser equipment 102 can couple or connect the LTE transceiver 206, andthe 5G NR receiver 208 to the antennas 202 to facilitate various typesof wireless communication. The antennas 202 of the user equipment 102may include an array of multiple antennas that are configured similar toor differently from each other. The antennas 202 and the RF front end204 can be tuned to, and/or be tunable to, one or more frequency bandsdefined by the 3GPP LTE and 5G NR communication standards andimplemented by the LTE transceiver 206, and/or the 5G NR receiver 208.By way of example and not limitation, the antennas 202 and the RF frontend 204 can be implemented for operation in sub-gigahertz bands, sub-6GHZ bands, and/or above 6 GHz bands that are defined by the 3GPP LTE and5G NR communication standards. Alternatively, the 5G NR receiver 208 maybe replaced with a 5G NR transceiver and operations describe herein asperformed by the 5G NR receiver 208 may performed by the 5G NRtransceiver.

The user equipment 102 also includes processor(s) 210 andcomputer-readable storage media 212 (CRM 212). The processor 210 may bea single core processor or a multiple core processor composed of avariety of materials, such as silicon, polysilicon, high-K dielectric,copper, and so on. The computer-readable storage media described hereinexcludes propagating signals. CRM 212 may include any suitable memory orstorage device such as random-access memory (RAM), static RAM (SRAM),dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), orFlash memory useful to store device data 214 of the user equipment 102.The device data 214 includes user data, multimedia data, applications,and/or an operating system of the user equipment 102, which areexecutable by processor(s) 210 to enable user interaction with the userequipment 102.

CRM 212 also includes a radio control manager 216, which, in oneimplementation, is embodied on CRM 212 (as shown). Alternately oradditionally, the radio control manager 216 may be implemented in wholeor part as hardware logic or circuitry integrated with or separate fromother components of the user terminal 102. In at least some aspects, theradio control manager 216 configures the RF front end 204, the LTEtransceiver 206, and/or the 5G NR receiver 208 to implement thetechniques for downlink-only fifth generation new radio describedherein.

Turning to the device diagram for the base station 104, the base station104 shown in FIG. 2 includes a single network node (e.g. an E-UTRAN NodeB). The functionality of the base station 104 may be distributed acrossmultiple network nodes and/or devices, and distributed in any fashionsuitable to perform the functions described herein. The base station 104includes antennas 218, a radio frequency front end 220 (RF front end220), one or more LTE transceivers 222, and one or more 5G NRtransceivers 224 for communicating with the user equipment 102. The RFfront end 220 of the base station 104 can couple or connect the LTEtransceivers 222 and the 5G NR transceivers 224 to the antennas 218 tofacilitate various types of wireless communication. The antennas 218 ofthe base station 104 may include an array of multiple antennas that areconfigured similar to or differently from each other. The antennas 218and the RF front end 220 can be tuned to, and/or be tunable to, one ormore frequency band defined by the 3GPP LTE and 5G NR communicationstandards, and implemented by the LTE transceivers 222, and/or the 5G NRtransceivers 224. Additionally the antennas 218, the RF front end 220,the LTE transceivers 222, and/or the 5G NR transceivers 224 may beconfigured to support beamforming, such as Massive-MIMO, for thetransmission and reception of communications with the user equipment102.

The base station 104 also includes processor(s) 226 andcomputer-readable storage media 228 (CRM 228). The processor 226 may bea single core processor or a multiple core processor composed of avariety of materials, such as silicon, polysilicon, high-K dielectric,copper, and so on. CRM 228 may include any suitable memory or storagedevice such as random-access memory (RAM), static RAM (SRAM), dynamicRAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flashmemory useful to store device data 230 of the base station 104. Thedevice data 230 includes network scheduling data, radio resourcemanagement data, applications, and/or an operating system of the basestation 104, which are executable by processor(s) 226 to enablecommunication with the user equipment 102.

CRM 228 also includes a base station manager 232, which, in oneimplementation, is embodied on CRM 228 (as shown). Alternately oradditionally, the base station manager 232 may be implemented in wholeor part as hardware logic or circuitry integrated with or separate fromother components of the base station 104. In at least some aspects, thebase station manager 232 configures the LTE transceivers 222 and the 5GNR transceivers 224 for communication with the user equipment 102, aswell as communication with the EPC 114. The base station 104 includes acore network interface 236 that connects the base station 104 to theservices implemented in the EPC 114 and/or to other base stations 104 toexchange data and control information to manage the communication ofvarious base stations 104 with the user equipment 102.

Closed-Loop Beamforming Feedback

In aspects, the user equipment 102 provides feedback to the base station104 for beamforming of the 5G NR downlink via the LTE anchor link. Forexample, beamforming for Massive MIMO uses closed-loop or beam-indexbeamforming for downlink-only 5G NR. The base station 104 and the userequipment 102 both have a copy of a codebook 234 that includes precodingmatrices for beamforming with an index value (e.g., a precoding matrixindicator or PMI) associated with each precoding matrix. The codebook234 can be stored in the CRM 212 of the user equipment 102 and in theCRM 228 of the base station 104.

FIG. 3 illustrates an example environment 300 in which various aspectsof downlink-only fifth generation new radio techniques can beimplemented. The environment 300 illustrates the user equipment 102providing feedback for beamforming the 5G NR downlink via the wirelesslink 106.

In aspects, to determine the precoding matrix for beamforming the 5G NRdownlink, the base station 104 transmits cell-specific reference signals(RS) distributed over various resource elements (RE) and/or timeslots ofthe 5G NR downlink. The user equipment 102 evaluates the receivedreference signals to estimate channel conditions between the basestation 104 and the user equipment 102. Based on the channel estimatefor each of the received cell-specific reference signals, the userequipment 102 selects a precoding matrix for beamforming the 5G NRdownlink transmissions. The user equipment 102 sends a response thatincludes the PMI of the selected precoding matrix, via the LTE anchoruplink, to the base station 104. The base station 104 uses the selectedprecoding matrix to beamform the 5G NR downlink to the user equipment.The process of determining the precoding matrix can be repeatedperiodically based on changes in channel quality, location changes ofthe user equipment 102, and so forth.

For example, a reference signal generator 302 generates cell-specificreference signals that are provided to the 5G NR transceiver 224 fortransmission over an RF channel 304, using the antennas 218. 5G NRdownlink signals 306 that are modulated with the cell-specific referencesignals are radiated from the antennas 218 (illustrated as 306-1 through306-n) via the RF channel 304 and are received at the antennas 202 ofthe user equipment 102. The 5G NR receiver 208 demodulates the received5G NR downlink signals 306 and provides the demodulated cell-specificreference signals to a channel estimator 308, which generates anestimate of the quality of the RF channel 304 from the receivedcell-specific reference signals.

Based on the channel estimate for each of the received cell-specificreference signals, a matrix selector 310 determines the best precodingmatrix to use for beamforming the 5G NR downlink from the base station104 to the user equipment 102. The matrix selector 310 includes, or hasaccess to, the codebook 234 and uses the codebook 234 to determine theprecoding matrix indicator (PMI) for the best precoding matrix to usefor beamforming the 5G NR downlink. The matrix selector 310 provides thePMI to the LTE transceiver 206. The LTE transceiver 206 transmits thePMI to the base station 104 in a message on a control channel, such as aPhysical Uplink Control Channel (PUCCH), a Physical Uplink SharedChannel (PUSCH), or the like. The PMI is received by the LTE transceiver222 in the base station 104 and provided to a precoder 312, which usesthe PMI as an index into the codebook 234 to lookup the precoding matrixfor beamforming. The precoder 312 uses the precoding matrix from thelookup in the codebook 234 to beamform transmissions of 5G NR downlinkby the 5G NR transceiver 224. Additionally and/or optionally, thechannel quality indicator (CQI) for the 5G NR downlink can betransmitted by the LTE transceiver 206 along with the PMI.

User Plane and Control Plane Signaling

FIG. 4 illustrates an example block diagram of a network stack model 400that characterizes a communication system for the example environment100, in which various aspects of downlink-only fifth generation newradio techniques can be implemented. The network stack 400 includes auser plane 402 and a control plane 404. Upper layers of the user plane402 and the control plane 404, share common lower layers in the networkstack 400.

The shared lower layers include a physical layer 406 (PHY layer 406), aMedia Access Control layer 408 (MAC layer 408), a Radio Link Controllayer 410 (RLC layer 410), and a Packet Data Convergence Protocol layer412 (PDCP layer 412). The physical layer 406 provides hardwarespecifications for devices that communicate with each other. As such,the physical layer 406 establishes how devices connect to each other,assists in managing how communication resources are shared betweendevices, and the like.

The MAC layer 408 specifies how data is transferred between devices.Generally, the MAC layer 408 provides a way in which data packets beingtransmitted are encoded and decoded into bits as part of a transmissionprotocol.

The RLC layer 410 provides data transfer services to higher layers inthe network stack 400. Generally, the RLC layer 410 provides errorcorrection, packet segmentation and reassembly, and management of datatransfers in various modes, such as acknowledged, unacknowledged,transparent modes.

The PDCP layer 412 provides data transfer services to higher layers inthe network stack 400. Generally, the PDCP layer 412 provides transferof user plane 402 and control plane 404 data, header compression,ciphering, and integrity protection.

The user plane 402 layers includes an Internet Protocol layer 414 (IP414), a Transmission Control Protocol/User Datagram Protocol layer 416(TCP/UDP 416), and applications 418 that transfer data via the wirelesslink 106. The IP layer 414 specifies how the data from application 418are transferred to a destination node. The TCP/UDP layer 416 is used toverify that data packets intended to be transferred to the destinationnode reached the destination node, using either TCP or UDP for datatransfers by the application 418.

The control plane 404 includes Radio Resource Control 420 (RRC 420) andmobility and session management 422. RRC 420 establishes and releasesconnections and radio bearers, broadcasts system information, performspower control, and so forth. Mobility and session management 422provides support for mobility management and packet data bearer contextsfor the user equipment 102.

In the user equipment 102, each layer in both the user plane 402 and thecontrol plane 404 of the network stack 400 interacts with acorresponding peer layer in the base station 104, the EPC 114, and/orthe remote service 118, to support user applications and controloperation of the user equipment 102 in the E-UTRAN 112.

In aspects, a 5G NR downlink between the base station 104 and the userequipment 102 is associated with an LTE anchor link that includes adownlink and/or an uplink. For downlink control and/or packet datacommunications via the 5G NR downlink that require a response to thebase station 104 from the user equipment 102, the user equipment 102transmits the response to the base station 104 via the LTE anchoruplink.

For example, an acknowledgement (ACK) and/or a negative acknowledgement(NACK) at the PHY layer 406 or the MAC layer 408, with respect tooperations performed at the PHY layer 406 or the MAC layer 408 for the5G NR downlink, is transmitted via the PUCCH or the PUSCH on the LTEanchor uplink from the user equipment 102 to the base station 104.

In another example, a 5G NR downlink has a bearer that is separate fromLTE bearers between the base station 104 and the user equipment 102.Acknowledgements and control messages in the RLC layer 410 related tothe 5G NR bearer downlink are sent to the base station 104 via the LTEanchor uplink.

In a further example, user-plane flow control messages for datatransfers over the 5G NR downlink are transmitted via the LTE anchoruplink. For TCP packets transferred via the 5G NR downlink, TCP flowcontrol packets are transmitted via the LTE anchor uplink.

In aspects, signaling for activation and deactivation, communication ofgrant information, 5G NR downlink measurements, and/or channel qualitymeasurements are communicated between the base station 104 and the userequipment 102 over the LTE anchor link. For example, Radio ResourceControl (RRC) messages and/or Media Access Control (MAC) controlelements (CE) to activate or deactivate the 5G NR downlink arecommunicated between the base station 104 and the user equipment 102over the LTE anchor link that is associated with the 5G NR downlink. Inanother example, resource elements (RE) that grant time and frequencyresources to the user equipment 102 for the 5G NR downlink aretransmitted from the base station 104 to the user equipment 102 over theLTE anchor downlink. The base station 104 can also communicate grantinformation for the LTE anchor link via the 5G NR downlink to the userequipment 102. In further aspects, the base station 104 communicatesactivation messages, deactivation messages, and/or grant information forthe 5G NR downlink over the 5G NR downlink, and/or communicatesactivation messages, deactivation messages, and/or grant information forthe LTE anchor link over the 5G NR downlink.

In aspects, measurement reports for the 5G NR downlink, or measurementsof 5G NR signals from other base stations, which are used for radioresource control or mobility management of the user equipment 102, aretransmitted to the base station 104 over the LTE anchor uplink. Forexample, mobility management measurements, such as Received SignalStrength Indicator (RSSI), Reference Signal Received Power (RSRP),and/or Reference Signal Received Quality (RSRQ) measurements related tothe 5G NR downlink are transmitted over the LTE anchor uplink from theuser equipment 102 to the base station 104. In another example, channelquality measurements used for modulation and coding scheme (MCS)control, such as the channel quality indicator (CQI) for the 5G NRdownlink are transmitted to via the PUCCH or PUSCH on the LTE uplinkfrom the user equipment 102 to the base station 104.

Example methods 500-800 is described with reference to FIGS. 5-8 inaccordance with one or more aspects of downlink-only fifth generationnew radio. Generally, any of the components, modules, methods, andoperations described herein can be implemented using software, firmware,hardware (e.g., fixed logic circuitry), manual processing, or anycombination thereof. Some operations of the example methods may bedescribed in the general context of executable instructions stored oncomputer-readable storage memory that is local and/or remote to acomputer processing system, and implementations can include softwareapplications, programs, functions, and the like. Alternatively or inaddition, any of the functionality described herein can be performed, atleast in part, by one or more hardware logic components, such as, andwithout limitation, Field-programmable Gate Arrays (FPGAs),Application-specific Integrated Circuits (ASICs), Application-specificStandard Products (ASSPs), System-on-a-chip systems (SoCs), ComplexProgrammable Logic Devices (CPLDs), and the like.

FIG. 5 illustrates example method(s) 500 of downlink-only fifthgeneration new radio as generally related to activation of, and datatransfer using, an LTE anchor link and a 5G NR downlink between the userequipment 102 and the base station 104. The order in which the methodblocks are described are not intended to be construed as a limitation,and any number of the described method blocks can be combined in anyorder to implement a method, or an alternate method.

At block 502, a user equipment attaches to a radio access network via abase station. For example, the user equipment 102 attaches to theE-UTRAN 112 via the base station 104. The attachment process may includea random access procedure, establishing a Radio Resource Control (RRC)connection, authenticating the user equipment 102 to the E-UTRAN 112,and/or requesting connectivity to a public data network (PDN).

At block 504, the user equipment activates one or more LTE bearers. Forexample, the user equipment 102 activates an LTE default bearer with theE-UTRAN 112. The user equipment 102 may additionally activate dedicatedbearers with the LTE network.

At block 506, the user equipment activates a 5G NR downlink-only bearervia the LTE anchor link. For example, the user equipment 102communicates signaling messages via the LTE anchor link to the basestation 104 to activate a bearer over the 5G NR downlink. Radio resourcecontrol (RRC) messages and/or Media Access Control (MAC) controlelements (CE) to activate the 5G NR downlink are communicated betweenthe base station 104 and the user equipment 102 over the LTE anchorlink.

At block 508, the user equipment receives grant information for the 5GNR downlink via the LTE anchor link. For example, the user equipment 102receives resource elements (RE) to configure the 5G NR receiver 208 touse time and frequency resources assigned to the 5G NR downlink.

At block 510, the user equipment transfers packet data via the 5G NRdownlink-only bearer and LTE anchor link. For example, the userequipment 102 receives packet data, via the 5G NR receiver 208, over the5G NR downlink. The user equipment 102 sends acknowledgements of thereceived packet data using the uplink of the LTE anchor link.

FIG. 6 illustrates example method(s) 600 of downlink-only fifthgeneration new radio as generally related to closed-loop beamforming ofthe 5G NR downlink. The order in which the method blocks are describedare not intended to be construed as a limitation, and any number of thedescribed method blocks can be combined in any order to implement amethod, or an alternate method.

At block 602, a user equipment receives reference signals via the 5G NRdownlink. For example, the user equipment 102 receives cell-specificreference signals (RS) distributed over various resource elements (RE)and/or timeslots of the 5G NR downlink that are transmitted by the basestation 104 on the 5G NR downlink.

At block 604, the user equipment estimates a channel condition for eachof the received reference signals. For example, the channel estimator308 in the user equipment 102 estimates a channel condition for each ofthe reference signals received from the base station 104.

At block 606, based on the estimates of the channel conditions, the userequipment selects a precoding matrix for beamforming the 5G NR downlink.For example, the matrix selector 310 in the user equipment 102 evaluatesthe estimates of the channel conditions and selects a precoding matrix,from a codebook 234 shared with the base station 104, to beamform the 5GNR downlink.

At block 608, the user equipment transmits an indication of the selectedprecoding matrix via the uplink of the LTE anchor link to the basestation. For example, the user equipment 102 transmits an index, such asa precoding matrix indicator (PMI), associated with the selectedprecoding matrix in the shared codebook 234, to the base station 104,via the LTE anchor link. The base station 104 uses the selectedprecoding matrix from the codebook 234 to beamform the 5G NR downlink.The PMI can be transmitted via a Physical Uplink Control Channel (PUCCH)or a Physical Uplink Shard Channel (PUSCH) via the LTE anchor link.

FIG. 7 illustrates example method(s) 700 of downlink-only fifthgeneration new radio as generally related to control-plane measurementsfor mobility management and/or channel quality of the 5G NR downlink.The order in which the method blocks are described are not intended tobe construed as a limitation, and any number of the described methodblocks can be combined in any order to implement a method, or analternate method.

At block 702, a user equipment activates an LTE anchor link and a 5G NRdownlink. For example, the user equipment 102 activates an LTE anchorlink and a 5G NR downlink from the base station 104, as described withrespect to FIG. 5, above.

At block 704, the user equipment measures radio and/or channelparameters of the 5G NR downlink. For example, the user equipment 102measures mobility management-related radio parameters, such as the RSSI,the RSRP, and/or the RSRQ, and/or channel quality measurements, such asthe CQI, related to the 5G NR downlink.

At block 706, the user equipment reports 5G NR downlink measurements viathe uplink of the LTE anchor link. For example, the user equipment 102reports the 5G NR downlink measurements to the base station 104 via theuplink of the LTE anchor link. The 5G NR downlink measurements may bereported separately from similar measurements of the LTE anchor link, orreported in combination with similar measurements of the LTE anchorlink.

FIG. 8 illustrates example method(s) 800 of downlink-only fifthgeneration new radio as generally related to acknowledgements of networklayer operations of the 5G NR downlink. The order in which the methodblocks are described are not intended to be construed as a limitation,and any number of the described method blocks can be combined in anyorder to implement a method, or an alternate method.

At block 802, a user equipment activates an LTE anchor link and a 5G NRdownlink. For example, the user equipment 102 activates an LTE anchorlink and a 5G NR downlink from the base station 104, as described withrespect to FIG. 5, above.

At block 804, the user equipment completes an operation in a layer ofthe network stack for the 5G NR downlink. For example, a networkoperation in the user equipment 102, which provides a response (e.g.,ACK, NACK, handshake, flow control message, and the like) for thecompletion of the network operation in the 5G NR network stack,completes the network operation and generates the response. The networkoperation includes PHY and/or MAC operations, TCP operations,application-related operations, and the like.

At block 806, the user equipment sends a response indicating thecompletion of the network operation via the uplink of the LTE anchorlink. For example, the user equipment 102 sends the response thatindicates the completion of the network operation in the 5G NR networkstack via the uplink of the LTE anchor link.

FIG. 9 illustrates an example communication device 900 that can beimplemented as the user equipment 102 in accordance with one or moreaspects of downlink-only fifth generation new radio as described herein.The example communication device 900 may be any type of mobilecommunication device, computing device, client device, mobile phone,tablet, communication, entertainment, gaming, media playback, and/orother type of device.

The communication device 900 can be integrated with electroniccircuitry, microprocessors, memory, input output (I/O) logic control,communication interfaces and components, as well as other hardware,firmware, and/or software to implement the device. Further, thecommunication device 900 can be implemented with various components,such as with any number and combination of different components asfurther described with reference to the user equipment 102 shown inFIGS. 1-3.

In this example, the communication device 900 includes one or moremicroprocessors 902 (e.g., microcontrollers or digital signalprocessors) that process executable instructions. The device alsoincludes an input-output (I/O) logic control 904 (e.g., to includeelectronic circuitry). The microprocessors can include components of anintegrated circuit, programmable logic device, a logic device formedusing one or more semiconductors, and other implementations in siliconand/or hardware, such as a processor and memory system implemented as asystem-on-chip (SoC). Alternatively or in addition, the device can beimplemented with any one or combination of software, hardware, firmware,or fixed logic circuitry that may be implemented with processing andcontrol circuits.

The one or more sensors 906 can be implemented to detect variousproperties such as acceleration, temperature, humidity, supplied power,proximity, external motion, device motion, sound signals, ultrasoundsignals, light signals, global-positioning-satellite (GPS) signals,radio frequency (RF), other electromagnetic signals or fields, or thelike. As such, the sensors 906 may include any one or a combination oftemperature sensors, humidity sensors, accelerometers, microphones,optical sensors up to and including cameras (e.g., chargedcoupled-device or video cameras), active or passive radiation sensors,GPS receivers, and radio frequency identification detectors.

The communication device 900 includes a memory device controller 908 anda memory device 910 (e.g., the computer-readable storage media 212),such as any type of a nonvolatile memory and/or other suitableelectronic data storage device. The communication device 900 can alsoinclude various firmware and/or software, such as an operating system912 that is maintained as computer executable instructions by the memoryand executed by a microprocessor. The device software may also include aradio control manager application 914 that implements aspects ofdownlink-only fifth generation new radio. The computer-readable storagemedia described herein excludes propagating signals.

The communication device 900 also includes a device interface 916 tointerface with another device or peripheral component, and includes anintegrated data bus 918 that couples the various components of thecommunication device 900 for data communication between the components.The data bus in the communication device 900 may also be implemented asany one or a combination of different bus structures and/or busarchitectures.

The device interface 916 may receive input from a user and/or provideinformation to the user (e.g., as a user interface), and a receivedinput can be used to determine a setting. The device interface 916 mayalso include mechanical or virtual components that respond to a userinput. For example, the user can mechanically move a sliding orrotatable component, or the motion along a touchpad may be detected, andsuch motions may correspond to a setting adjustment of the device.Physical and virtual movable user-interface components can allow theuser to set a setting along a portion of an apparent continuum. Thedevice interface 916 may also receive inputs from any number ofperipherals, such as buttons, a keypad, a switch, a microphone, and animager (e.g., a camera device).

The communication device 900 can include network interfaces 920, such asa wired and/or wireless interface for communication with other devicesvia Wireless Local Area Networks (WLANs), wireless Personal AreaNetworks (PANs), and for network communication, such as via theInternet. The network interfaces 920 may include Wi-Fi, Bluetooth™, BLE,and/or IEEE 802.15.4. The communication device 900 also includeswireless radio systems 922 for wireless communication with cellularand/or mobile broadband networks. Each of the different radio systemscan include a radio device, antenna, and chipset that is implemented fora particular wireless communications technology, such as the antennas202, the RF front end 204, the LTE transceiver 206, and/or the 5G NRreceiver 208. The communication device 900 also includes a power source924, such as a battery and/or to connect the device to line voltage. AnAC power source may also be used to charge the battery of the device.

Although aspects of downlink-only fifth generation new radio have beendescribed in language specific to features and/or methods, the subjectof the appended claims is not necessarily limited to the specificfeatures or methods described. Rather, the specific features and methodsare disclosed as example implementations of downlink-only fifthgeneration new radio, and other equivalent features and methods areintended to be within the scope of the appended claims. Further, variousdifferent aspects are described and it is to be appreciated that eachdescribed aspect can be implemented independently or in connection withone or more other described aspects.

The invention claimed is:
 1. A mobile communication device comprising: aradio frequency transceiver; a radio frequency receiver; and a processorand memory system to implement a radio control manager applicationconfigured to: establish an LTE anchor link with a base station usingthe radio frequency transceiver; establish a 5G NR downlink from thebase station to the mobile communication device using the radiofrequency receiver; and manage the 5G NR downlink using an uplink of theLTE anchor link.
 2. The mobile communication device of claim 1, whereinthe 5G NR downlink from the base station to the mobile communicationdevice is beamformed, the radio control manager application configuredto: receive reference signals from the base station with the radiofrequency receiver; estimate a channel condition for each of thereceived reference signals; based on the estimation of the channelconditions, select a precoding matrix to use for beamforming the 5G NRdownlink by the base station; and transmit an indication of the selectedprecoding matrix to the base station using the uplink of the LTE anchorlink, the transmission being effective to cause the base station tobeamform the 5G NR downlink using the selected precoding matrix.
 3. Themobile communication device of claim 2, wherein the precoding matrix isselected from a codebook, wherein the codebook is shared between themobile communication device and the base station, and wherein theindication of the selected precoding matrix is an index into thecodebook usable to access the selected precoding matrix.
 4. The mobilecommunication device of claim 2, wherein the indication of the selectedprecoding matrix is a Precoding Matrix Indicator (PMI), and wherein thePMI is transmitted from the mobile communication device to the basestation via a Physical Uplink Control Channel (PUCCH) or a PhysicalUplink Shared Channel (PUCCH).
 5. The mobile communication device ofclaim 1, wherein the management of the 5G NR downlink comprisesacknowledging a physical layer operation at the radio frequency receiverand wherein the acknowledgement of the physical layer operation at theradio frequency receiver is transmitted to the base station using theuplink of the LTE anchor link.
 6. The mobile communication device ofclaim 1, wherein the management of the 5G NR downlink comprisesacknowledging a Media Access Control (MAC) layer operation at the radiofrequency receiver and wherein the acknowledgement of the MAC layeroperation at the radio frequency receiver is transmitted to the basestation using the uplink of the LTE anchor link.
 7. The mobilecommunication device of claim 1, wherein the management of the 5G NRdownlink comprises sending a flow control message related to user-planepacket data received by the radio frequency receiver and wherein theflow control message is transmitted to the base station using the uplinkof the LTE anchor link.
 8. The mobile communication device of claim 1,wherein the management of the 5G NR downlink comprises measuring radioparameters related to the 5G NR downlink, wherein a measurement reportincludes the measured radio parameters, and wherein the measurementreport is transmitted to the base station using the uplink of the LTEanchor link.
 9. The mobile communication device of claim 8, wherein themeasured radio parameters include one or more of: a Received SignalStrength Indicator (RSSI), a Reference Signal Received Power (RSRP), ora Reference Signal Received Quality (RSRQ).
 10. The mobile communicationdevice of claim 1, wherein the management of the 5G NR downlinkcomprises measuring a channel quality related to the 5G NR downlink, andwherein the channel quality measurement is transmitted to the basestation using the uplink of the LTE anchor link.
 11. The mobilecommunication device of claim 10, wherein the channel qualitymeasurement includes a channel quality indicator (CQI), and wherein theCQI is transmitted from the mobile communication device to the basestation via a Physical Uplink Control Channel (PUCCH) or a PhysicalUplink Shared Channel (PUCCH).
 12. The mobile communication device ofclaim 1, wherein the establishment of the 5G NR downlink comprisesgranting resource elements (RE) for the 5G NR downlink to the mobilecommunication device, and wherein the resource elements for the 5G NRdownlink are transmitted from the base station to the mobilecommunication device over the LTE anchor link.
 13. A method of managinga fifth generation new radio (5G NR) downlink from a base station to auser equipment (UE), the method comprising: establishing, by the UE, aLong Term Evolution (LTE) anchor link with the base station;establishing the fifth generation new radio (5G NR) downlink from thebase station to the UE; and managing, by the user equipment, the 5G NRdownlink using an uplink of the LTE anchor link.
 14. The method of claim13, wherein the 5G NR downlink from the base station to the userequipment is beamformed, the method comprising: receiving referencesignals from the base station; estimating a channel condition for eachof the received reference signals; based on the estimating the channelconditions, selecting a precoding matrix to use for beamforming the 5GNR downlink by the base station; and transmitting an indication of theselected precoding matrix to the base station via the uplink of the LTEanchor link, the transmitting being effective to cause the base stationto beamform the 5G NR downlink using the selected precoding matrix. 15.The method of claim 13, the managing of the 5G NR downlink comprising:measuring radio parameters related to the 5G NR downlink by the userequipment, the radio parameters including one or more of: a ReceivedSignal Strength Indicator (RSSI), a Reference Signal Received Power(RSRP), or a Reference Signal Received Quality (RSRQ); and sending ameasurement report including the measured radio parameters to the basestation using the uplink of the LTE anchor link.
 16. The method of claim13, the establishing the 5G NR downlink comprising: receiving a grant ofresource elements (RE) for the 5G NR downlink, the grant of the RE beingreceived from the base station over the LTE anchor link.
 17. A systemcomprising: an Evolved Universal Terrestrial Radio Access Network Node B(E-UTRAN Node B); and a user equipment (UE) configured to: establish aLong Term Evolution (LTE) anchor link with the E-UTRAN Node B using aradio frequency transceiver; establish a fifth generation new radio (5GNR) downlink from the E-UTRAN Node B to the user equipment using a radiofrequency receiver; and manage the 5G NR downlink using an uplink of theLTE anchor link.
 18. The system of claim 17, wherein the 5G NR downlinkfrom the E-UTRAN Node B to the user equipment is beamformed, the userequipment configured to: receive reference signals from the E-UTRAN NodeB; estimate a channel condition for each of the received referencesignals; based on the estimate of the channel conditions, select aprecoding matrix to use for beamforming the 5G NR downlink by theE-UTRAN Node B; and transmit an indication of the selected precodingmatrix to the E-UTRAN Node B using the uplink of the LTE anchor link,the transmission being effective to cause the E-UTRAN Node B to beamformthe 5G NR downlink using the selected precoding matrix.
 19. The systemof claim 17, wherein the management of the 5G NR downlink comprisesmeasuring channel quality related to the 5G NR downlink to produce achannel quality indicator (CQI), the user equipment configured to:transmit the CQI to the E-UTRAN Node B via a Physical Uplink ControlChannel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) using theuplink of the LTE anchor link.
 20. The system of claim 17, wherein theestablishment of the 5G NR downlink comprises granting resource elements(RE) for the 5G NR downlink to the user equipment, and wherein theresource elements for the 5G NR downlink are transmitted from theE-UTRAN Node B to the user equipment over the LTE anchor link.